Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines

摘要

The palladium(II) bis-chelate complexes of the type [Pd(TSC~(1-5))_2] (6-10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC~1 (1), 4-phenyl-1-(2'-chloro-benzaldehyde)-thiosemicarbazone, HTSC~2 (2), 4-phenyl-1-(3'-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC~3 (3), 4-phenyl-1-(2'-naphthaldehyde)-thiosemicarbazone, HTSC~4 (4), and 4-phenyl-1-(1'-nitro-2'-naphthaldehyde)-thiosemicarbazone, HTSC~5 (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and ~1H- and ~(13)C-NMR). The molecular structure of HTSC~3, HTSC~4, and [Pd(TSC~1)_2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to Pd~(II) through the azomethine nitrogen and thione sulfur atoms in a cis arrangement. The in vitro cytotoxic activity measurements indicate that the palladium(II) complexes (IC_(50) = 0.01-9.87 μM) exhibited higher antiproliferative activity than their free ligands (IC_(50) = 23.48-70.86 and >250 μM) against different types of human tumor cell lines. Among all the studied palladium(II) complexes, the [Pd(TSC~3)_2] (8) complex exhibited high antitumor activity on the DU145 prostate carcinoma and K562 chronic myelogenous leukemia cells, with low values of the inhibitory concentration (0.01 and 0.02 μM, resp.).